This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Xenorhabdus scapteriscii is a gamma proteobacter isolated from an entomopathogenic nematode. The bacterium was found to produce and secrete a 1350D molecule that is orally lethal to Aedes aegypti mosquito larvae in picogram levels. It is not toxic to other insects or animals, The toxin is purified by acetone precipitation of growth liquor followed by ion exchange and reverse phase chromatography. The toxin is produced in defined media containing glycerol as carbon and energy source and ammonium sulfate as N source. The toxin will be prepared from media containing C13 glycerol and N15 ammonium for NMR analyses.